Method for secure component labeling in images

Abstract

A method processes an input image securely. An input image is acquired in a client and partitioned into a set of overlapping tiles. The set of overlapping tiles is transferred to a server. In the server, motion pixels in each tile that are immediately adjacent to other motions pixels in the tile are labeled locally to generate a set of locally labeled tiles. The set of locally labeled tiles is transferred to the client. In the client, the set of locally labeled tiles is labeled globally to generate a list of pairs of unique global labels. The list of pairs of unique global labels is transferred to the server. In the server, the pairs of unique global labels are classified into equivalence classes. The equivalence classes are transferred to the client and the motion pixels are relabeled in the client according to the equivalence classes to form connected components in the input image.

1. A method for processing an input image securely, comprising:
 acquiring, in a client, an input image; 
 partitioning the input image into a set of overlapping tiles; 
 transferring the set of overlapping tiles to a server; 
 labeling locally, in the server, motion pixels in each tile that are immediately adjacent to other motions pixels in the tile to generate a set of locally labeled tiles; 
 transferring the set of locally labeled tiles to the client; 
 labeling globally, in the client, the set of locally labeled tiles to generate a list of pairs of unique global labels; 
 transferring the list of pairs of unique global labels to the server; 
 classifying, in the server, the pairs of unique global labels into equivalence classes; 
 transferring the equivalence classes to the client; and 
 relabeling, in the client, the motion pixels according to the equivalence classes to form connected components in the input image. 
 
   
   
     2. The method of  claim 1 , in which each tile includes 3×3 pixels, and adjacent tiles overlap by one pixel in each direction. 
   
   
     3. The method of  claim 1 , in which the set of overlapping tiles includes fake tiles. 
   
   
     4. The method of  claim 1 , in which the set of overlapping tiles are transferred to the server in a random order.